The invention relates to a process for preparing homo- or co-polymers of ethylene, in which ethylene alone or mixed with one or more other unsaturated organic compounds capable of forming a copolymer with ethylene, is subjected to a high pressure and a high temperature in a reactor in the presence of an initiator or a catalyst, in which the mixture of polymer and uncoverted monomer discharged out of the reactpr is expanded to, essentially atmospheric pressure with the aid of an expansion device in two or more steps, and in which the polymer present in the expanded mixture is separated from the mixture in the solid state.
A process of this kind is known from the U.S. Pat. No. 2,831,845 and 3,719,648, the disclosures of which are incorporated herein by reference. In these known processes the mixture discharged out of the reactor is so expanded that a mist of fine polymer droplets forms in the ethylene, which droplets are rapidly cooled by water or cold ethylene, so that a powdery polymer is obtained.
It has now been found that under certain conditions a fibrous polymer is obtained which is suitable for the manufacture of sheets, fleeces and similar non-woven products under either wet or dry processing conditions, or for use as a binding agent in the manufacture of non-woven products from natural or synthetic fibers.